Magnetic Helical Robot for Targeted Drug-Delivery in Tubular Environments

We propose a novel magnetic helical robot (HR) that can helically navigate, release a drug to a target area, and generate a mechanical drilling motion to unclog tubular structures of the human body. The proposed HR is composed of two rotating cylindrical magnets (RMs), four fixed cylindrical magnets (FMs), and a helical body. The RMs can be rotated in different directions under two orthogonal external rotating magnetic fields (ERMF). Utilizing these ERMFs, we can generate various motions. The ERMF along the axis of the RMs can generate the drug-release motion, while the ERMF orthogonal to the axis of the RMs can generate navigating and drilling motions. On the other hand, the magnetic torque and the attractive magnetic force between RMs and FMs tightly seal the nozzles in the drug chamber. We analyze these magnetic torque and force of the magnets for the navigating, drug-release, and drilling motion. Especially, the drug-release motion utilizes an eccentric rotational motion of the RMs due to the attractive and repulsive magnetic force between RMs and FMs. This motion squeezes and discharges the drug through a nozzle. We designed the mechanical structure of the proposed HR considering the magnetic properties to achieve the proposed functions. Finally, we prototyped the HR and conducted several experiments to verify the navigating, drug-delivery and drilling capabilities of the HR. We also confirmed that drug-enhanced drilling could unclog the clogged area more effectively than the simple drilling motion.